Duramax Oil Changes

[illapah]

What I think is happening here is that 'Jil' is getting a baseline for future oil change intervals based on her driving habits at the time of sample.

If I was one to change every 3K (or even 5K) miles I wouldn't concern myself with oil analysis. If I was to try to wring the most miles out of an oil change however, I would be real interested in how long I could run without danger of damage.

Kind of like getting an appraisal on a home. One does't get a new appraisal for each buyer I would think.

[Montana Sky]

Illapah,
Thank you for the clarification. I was a little confused on where the cost savings was by spending $10 - $30 to have my oil tested every time between changes. I understand now.

[Cat320]

quote:Originally posted by ARJ

I have spoken with quite a few folks both at dealers and at my local freightliner dealer about frequency of oil changes. The consensus is 3k miles even if using synthetic (this applied to 18 wheelers too from what I understood). The reason I get is because of the crap in the oil rather than the oil breaking down. I suppose one could change only the filter and extend the change cycle. However, the price of oil vs the price of an engine is enough to convince me to stick with my 3k interval.

I sure would like to know who is advising you to change the oil at 3k intervals...especially using synthetic. When I was doing the research before buying my truck, I visited four Chevy dealers and one GM dealer...they all said to go by the DIC. The only ones I have heard preaching the 3k philosophy are guys operating quickie oil change shops. If 18 wheelers were to follow this schedule, the would be changing oil once a week. Plus filling an 18 wheeler with oil would be a very costly experience. Just MHO, but I think you are getting bad advice...3k oil changes went out with adjusting the carburetor.

[DonandBonnie]

What's a carburetor?

If the Duramax oil intervals are determined by a combination of the engine rotation and oil temperatures, will a higher price synthetic oil run at cooler temperatures and will that be enough to justify the extra expense of the oil?

[MAMalody]

I don't think the 3k mile oil change went our with carbs. The Ford PSD book indicates if used under heavey load to change the oil at 3k intervals.

[ARJ]

quote:Originally posted by Cat320

I sure would like to know who is advising you to change the oil at 3k intervals...especially using synthetic. When I was doing the research before buying my truck, I visited four Chevy dealers and one GM dealer...they all said to go by the DIC. The only ones I have heard preaching the 3k philosophy are guys operating quickie oil change shops. If 18 wheelers were to follow this schedule, the would be changing oil once a week. Plus filling an 18 wheeler with oil would be a very costly experience. Just MHO, but I think you are getting bad advice...3k oil changes went out with adjusting the carburetor.

I guess we first need to compare apples to apples. My Duramax supplement specifies 5k miles oci for short trips, and 7.5k for long trips. It does not specify towing requirements.

Second, I always have my oil changed at a GM or Chevy dealer. Cost? I supply my own oil (Delo 400 $6/gal) and filter (Baldwin B1441 $4.66). The times I have had it changed range from a high of $13.00 to $11.95 for labor w/no bitching about me having my own oil/filter. I can also get the truck washed if I ask and one dealer in MT (Tyler Chevy) washed it without my even asking. It is well worth the insignificant cost to have the work done at a dealer because they check the rest of the truck at the same time and I don't have to run to Checker to dump the old oil. I usually run between 3k and 4.5k on changes.

Every one of the dealers (from ME to CA) I have used in 68k miles has put a sticker in the windshield indicating that the next change is supposed to be 3 thousand miles from the one I just had done.

BTW, I change my own fuel filter between 12 & 15k mi (Baldwin $18.18) and my own tranny filter ( Baldwin 9.42)& fluid.

And that's all I have to say about that!

[Bob Pasternak]

ARJ: When I retired from driveing the big ones in 1993 I didn't know of anybody changing oil at less than 18,000 miles. When I was living in FL and running a round a week FL to Los Angeles we'd have had to change it twice a week. At 12 gals a change, that'd get expensive. I think the interval now is about 50,000 miles.

[Cat320]

The new Chevys (at least 05s on) do not give mileage recommendations for oil changes. They say to do it when the DIC says it's time or at one year, which ever comes first.

[rickety]

I have the Amsoil dual filtration sytem on my Dura. One is a high bypass filter and one is a full flow filter (both are one quart in size). I also have the oil checked (tested) every six months. It has come back clean the two times I have had it done. I have 29000 miles on the truck, and theoil shoed no contaminants to speak of. I am having the iol changed with the filters in March, that will be after 16000 miles. It will cost about
$120 for all. I also have Amsoil in tranny and rear end. No wear shown in either of those applications.

It took me over 6 months to decide to change to synthetics, and then only after talking to my Chevy dealer and to various diesel mechanics I know, and then doing cost analyses on this stuff and I actually save money doing it this way!
Just my two cents worth allowing for inflation

[Geo5Sue]

Is anyone using oil between changes? I have added a quart every 3500 miles. GM says this is normal, the diesel page says:
"The longer oil drain intervals we see now in current vehicles lulls some owners to think they can forget about checking the oil. I've had this problem myself. The bottom line is that 2 quarts of oil consumption in 7,000 miles is relatively low oil usage.

GM considers 1 quart per thousand miles as excessive. I consider 1 quart oil consumption in 2000 miles a bit too much. My 2001 Duramax uses about 2 quarts in 7000 miles.

Jim


TheDieselPage.com
Jim Bigley
418 Grandview Drive
Stevensville, MT 59870
http://www.TheDieselPage.com
https://thedieselpage.com/form.htm (Secure Online Application) turbo@TheDieselPage.com"

[DonandBonnie]

With only 760 miles on the Duramax, its still a bit early to detect oil consumption. I did not see anything out of the ordinary at the last (2nd) fill up. I'll certainly keep an eye on the dip stick and report anything unusual.

[Montana Sky]

One the highway road trips where I run 5,000 miles (empty) between changes, I have not noticed any oil useage. Stick still reads full and dealership has never mentioned anything.

[sreigle]

Did anyone answer the question about how the computer determines remaining oil life? Or did I miss that post? We likely will be in the truck market this summer as we approach the 100k end of warranty mark and I will consider all three majors. So I'm interested in this feature. My Ford does not have that.

I've been running Rotella T synthetic and changing oil at 10k miles (a good thing since it takes 15 quarts of oil) for the past 36k miles. The truck has 74k on it now and still is right on the full mark at oil change time with no oil additions. It seems to be doing fine on the synthetic. We hit the 10k mark about every 3 to 4 months so the 1 year issue is not a factor here. The tranny and the differential in the Ford come with synthetic from the factory. There is a recommended change interval on the tranny (30k miles) but the differential is supposedly a lifetime lube, per the manual.

[Montana Sky]

Steve,
Here are a few links for GM Vehicles. Hope this will help answer some questions...
http://www.gm.com/company/gmability/...qa_040104.html
http://www.onstar.com/us_english/jsp...s/oil_life.jsp
http://www.gmgoodwrench.com/_res/pdf...ConsumerQA.pdf
http://www.practicingoilanalysis.com...up=Lubrication

[DonandBonnie]

Steve,
The closest that was posted was that the percentage is determined by a combination of rpm's and temperature. I am still wondering if synthetic oil will run at lower temperatures and thus extend the time between oil changes. I am planning on visiting a couple of different Chevy service managers next week to see what answers they give me. Hopefully, they will both give me the same answer. I'll post what I find out.
Don

[Montana Sky]

Don,
Here is GM's take~
"I use synthetic oil. Should I expect to get more miles before the GM Oil Life System indicates I need an oil change?"

"The GM OLS bases its calculations on the factory fill requirement. While you may experience some benefits from the use of synthetic oil, it does not extend the your vehicles required oil-drain interval."

[DonandBonnie]

Montana Sky,
Looks like we were both posting at the same time. Your research seems to answer the question. At this point, I see no reason to use an expensive synthetic oil. I'll stick with a good grade recommended oil and change it as the intervals arrive. I still find it hard to believe that my truck is smart enough to tell me when it needs its oil changed.

[Montana Sky]

Don,
I admit I have never followed the OLS on either of my Duramax's. For towing and normal every day city/highway driving, my truck gets 3,000 mile oil changes. Only on the highway trips with no towing will I run the oil out to 5,000 mile changes. This is just what works for me.

[BigAl52]

Some time back there was a thread on synthetic oil. I made a statement then about extended drains. There here and they are only going to get longer. I here the new Dodge for 08 will have 20000 mile oil changes. Cummins told our company 35000 on the Signature motors 600hp. The company that I work for has been doing those changes for quite some time. No problems yet. Went to a GM dealer yesterday to have the oil changed on the wifes new 2007 Avalanche. They carry Mobil 1. They asked me what kinda oil I wanted in the truck. I told them I wanted whatever oil came with the free oil change that the dealer gave me. I also mentioned that I was going to put Amsoil in the vehicle when it was due. His reply was that Amsoil was number one in his book and that he should'nt even say that because they sell Mobil 1. Mobil makes Goodwrench oil for those who don't know that. He was also a believer in the extended drains. Engines are running cleaner and longer therefore the reason for the extension. Just my .02 cents worth. Al